1. Field of the Invention
The present invention relates to a mechanical transmitting device for a feeding mechanism of an information recording/reproducing apparatus, and particularly to a transmitting device which can effectively dampen shock of an optical pickup unit caused by accidental dropping or bumping.
2. Description of the Prior Art
In recent years, optical discs such as CDs (Compact Discs), DVDs (Digital Video Discs or Digital Versatile Discs) and MDs (Mini Discs) have been developed as large capacity, high-density media for recording a variety of information. It is very convenient to carry around such storage media.
An optical recording/reproducing apparatus can reproduce high-density information recorded on an optical disc, and can record information on an optical disc at a high density. An optical pickup unit of the optical recording/reproducing apparatus moves along radial directions of the optical disc to reproduce or record the information. Because a driving mechanism of the optical pickup unit is precisely designed, a base of the pickup unit seldom sustains accidental shock. Nevertheless, in practice, accidents involving the information recording/reproducing apparatus often happen. On certain of such occasions, for example when the information recording/reproducing apparatus is accidentally dropped to the ground, the optical pickup unit may bump against other parts of the optical recoding/reproducing apparatus and may even itself sustain damage.
Referring to FIG. 4, a typical information recording and reproducing apparatus 9 is shown. A pickup module 2 is movably fixed on a base 3, the pickup module 2 being movable along radial directions of a disc (not shown). The pickup module 2 is driven by a transmitting member 7 transmitting output power of a stepping motor (not labeled). The transmitting member 7 comprises an engaging portion 4 engaged with a feeding screw (not labeled) of the stepping motor, and a linking portion 5 engaged with the base 3. The feeding screw is located between two parallel bearing portions 6a, 6b fixed to a chassis 1. Two stopper projections 5a, 5b respectively extend outwardly from the linking portion 5 in directions parallel to the feeding screw. The stopper projections 5a, 5b are first to against the bearing portions 6a, 6b respectively, such that the base 3 with the pickup module 2 thereon is prevented from severely bumping against other parts of the information recording and reproducing apparatus 9. This kind of mechanism is disclosed in European Patent Application No. EP1058243A1.
However, when the ends of the stopper projections 5a, 5b come into contact with the bearing portions 6a, 6b, a great amount of shock may be transmitted to the pickup module 2 via the base 3. The precision mechanism of the pickup module 2 is liable to sustain damage that causes malfunction or even complete failure.